Double-casing high-pressure pump



NVENTOR y ATTQRNEY Oct. 1, 1946. E. HART DOUBLE CASING HIGH PRESSURE PUMP Filed Julyl', 1944 A2 sheets-Sheet 1.

Octyl, 1946. E, HAR-l1 2,408,637'

DOUBLE CASING HIGH PRESSR PUMP I Filed July 5l, 1944 2 Sheets-Sheekf 2 KZ] mwMM-l k ml m mY N MZ...Y

INVENTQR 1 EDWARD HART BW if@ ATTORNEY Y The object of the Patented Oct. 1, 1.946 f UNITED s'lirrss PATENT formes Edward Hart, San Marino, Calif., assignor to A. 0.`- Smith Corporation, Milwaukee, Wis., a corporation of NewYork Applieatin July 31, 1944, Serial No. 547,423',

f2 claims. (ci. loss-10s) This invention relates to kdouble casing high pressure pumps of the multi-stage rotary iinpeller type wherein the vpump housing `for the y impellers is of cast construction embodying passages and volutes giving. a high efliciency to the pump,.and wherein an .outer c as ing surrounds thepump housing and is adapted tocontainflud under pressure to support the pump housing against tension stresses resulting from the compression of the fluid therein. 'Ihe fluid in the casing is usually pumped :Iluid which is under the same pressure as the uid being dischar-ged from the pump.

. Heretofore, the outer casings for such pumps have been of cast or similar construction requiring heavy walls to withstand the high internal fluid pressures. Where corrosion was likely, either the metal of the casing throughout its thickness had to be` of an expensive corrosion resistant alloy, or else an added weight of some alloy sheet liner .had to be inserted therein and properly vsealed against leakageiof 4fluid behind the same. Such pumps were expensive and heavy in Weight, detracting from ytheir commercial applications;

ly reduce the cost of such pumps and to lighten the'iweightof theV same so that they may be employed'more readily in competition with other types of pumps.

According to the invention the outer casing is composed of a number of relatively thin layers of metal superimposed and welded along one or more longitudinal seams and Welded to end ilange members or closures for supporting the pump therein. Where corrosion is encountered, the inner layer is constructed of suitable corrosion resistant alloy While the remainder may be of less costly steel, all of the layers being'utilized for the retentionv ofthe pressure fluid.

Expensive casting operations yfor the casing are eliminated, and due to the higher quality of rolled stock of relatively. thin plates, the total wall thickness and Weight of the casing is considera-bly reduced. The layers are fabricated in tight contact to effectuniform stress distribution therein, While the flexibility of the several layers provides, a structure more kfree from' fabrication stresses and more reliable in the conning of the pressure uid.

The accompanying drawings illustrate an embodiment of the invention.

In the drawings:

Figure 1 is a side elevation with parts broken present invention is to greaty rvaway vand sectioned showing the. right hand .end of the pump; and w.

Fig 2 is a similar section throughthe left'hand endofthepuinp-` The pump comprises* a' cast lpump housing I having a rotaryV shaft 2 extending longitudinally axially thereof. The left hand end of housing I is bolted tothe cover plate 3. and the right hand end has a slip joint sealed by the annular ring 5 and centering the housing in a separator piece forming the inner Wall of a ysuction chamber in the endr housing 4. End housings tare .bolted to cover plate 3 and housing 4, respectively, and contain bearings for the ends of the pumpshaft 2. The shaft extends through the end of one kof the housings 6 to be driven by any suitable means..

TheA housing I containsV the impellersA-.l seh cured on .the shaft 2' in volute chambers 8.1111 the housing. As manyimpellers I may belemploy'ed as desired Within the limits of` proper' shaft alignment and support, the pump illustrated having ten impellers and being a ten-stage.- pump.

The inlet for the pump is` provided in end'housing 4 Where the lateral intake 9 supplies fluid to a throated circumferential chamber I0 leading. to the first stage impeller Il. From impeller Vof the outer cylindrical casing I4 by thearc deposit I5. The cover plate 3 is bolted to an end ange member I6r Welded to the opposite end of the casing I 4 by the arc deposit I 1. Welds I5 and I'I serve to secure the members longitudinally and the bolted end plate 3 and liange I6 provi-de for assembly of the pump.

In .accordance with the invention, the casing I4 is constructed of a plurality of layers of rolled plate formed into superimposed cylindrical layers to provide a multi-layer construction in which each layer is in uniform pressure engagement With its adjacent layervor layers.

In constructing the casing, the first layer I8 is rst formed by rolling or pressing a ilat plate to cylindrical shape and the longitudinal seam is welded, as by an arc deposit I9. Subsequent layers 20' are similarly formed and then applied either successively or at one time and tightened upon the inner layer by tension bands and then Welded along the longitudinal seams 2I. As many subsequent layers may be applied as may be stresses from fabrication, and the shop equipment for constructing the casing from such layers-is simple and inexpensive. tively thin layers provide a structure which is highly flexible to stresses and which effects a ready and uniform distribution of the working stresses throughout the same. y

The inner layer I8 may be of non-corrosive Furthermore, the relaalloy of a composition known to be resistant to attack from the fluid being pumped, and is welded into the structure in a manner adapting it totake its share of stress under working loads, along with the other layers.A

The casing I4 has a central discharge outlet i2 disposed in alignment with the loutlet port I2 of the pump housing I. The space or chamber 2t between housing I and casing III serves toretain pumped fluid under pressure from said outlet I2 and to thereby surround the pump housing I during operation with fluid under pressure.

By reason of the protection of housing I by the external vfluid pressure the housing can be thinner and much lighter in weight, thereby making the casting of it less expensive and its handling during machining and fabrication of the pump less difficult.

The outer casing withstands both the longitudinal and circumferential pressure of the fluid,

thereby relieving the pump housing of all tension stress during operation of the pump.

The invention may have various embodiments within the scope of the accompanying claims.

I claim:

1. In a double casing high pressure pump of the class described, an outer cylindrical casing constructed of a plurality of superimposed layers of rolled metal plate welded in close pressure engagement with one another for withstanding high internal fluid pressures, a lateral intake head pump.

4. welded to said casing at one end and a flange welded to the casing at the other end, an end head secured to said flange, aligned bearings carried by said heads for a pump shaft, a pump enclosed in said casing and having a rotary shaft extending therethrough and mounted in said end bearings, a plurality of impellers mounted on said shaft and operative in series to provide a high pressure discharge for the vpumped fluid, said vpump being supported at its ends only by said end heads and being continuously and radially spaced from said outer casing to provide a closed cham- Iber therebetween for substantially the full length y of the pump, and a lateral discharge outlet welded to saidfcasing.substantially centrally thereof in alignment with the discharge port of the pump and connecting with the space between said pump yto the end ofthe casing and another end head removably secured to the casing, a pump enclosed in said casing and havinga rotary shaft extending-therethrough and mounted in said end heads, a plurality of impellers mounted on said shaft and operative in series to provide a high pressure discharge `for the pumped fluid, said pump being supported only by said endV heads and being continuously and radially spaced from said outer casing throughout substantially the full length of the pump, and means comprising a discharge outlet disposed substantially centrally of the casing and connecting with the space between said purnp and casing to provide fluid between the pump and casing under a circumferential and longitudinal pressure equal to the pressure of the fluid at said discharge to protect the pump against internal fluid pressures during operation of -the EDWARD HART. 

